The nucleotide sequence of gene segment 1 of the porcine rotavirus Gottfried strain (which shares neutralization specificity with human rotavirus serotype 4 via VP7) was determined. This gene segment encodes VP1 which is present in single-shelled rotavirus particles. Other scientists have suggested that VP1 provides virus transcriptase and replicase enzymatic activities. Gene segment 1 was shown to be 3302 nucleotides in length and had a single open reading frame capable of encoding a protein of 1088 amino acids. The Gottfried strain porcine rotavirus VP1 was observed to share 5 consensus sequences with RNA-dependent RNA polymerases of 8 different plant and animal single-stranded RNA viruses. Thus, our analysis suggests that VP1 plays a role in mRNA synthesis. In addition, VP3, which is also present in single shell rotavirus particles, exhibits GTP-binding activity. This suggests that VP3 has mRNA capping enzyme activity.